The effect of deep impurities on the photoelectric effect in a strongly biased, high-resistance MSM structure during illumination with monochromatic light (hnu greater-than-or-equal-to E(g)) is examined theoretically. The complete system of equations, consisting of continuity equations in the diffusion-drift approximation and the Poisson equation, is solved. Thermonic emission of carriers across the metal-semiconductor surface is taken into account at the boundaries. Results on a Au-CdTe-Au structure with a single impurity level are reported. For the dark case it is shown, in particular, that the current j is a nonmonotonic function of the impurity concentration N(t). At low values of N(t) the current is an electron current, decreases linearly with increasing N(t), and is proportional to the applied voltage V. At N(t) above a certain characteristic value, the current is a hole current and proportional to square-root N(t)V. There is a region of a strong field near the anode. The threshold illumination intensities, below which the distributions of the electric field and the current are the same as the dark distributions, are determined. As the illumination intensity is raised above a certain threshold value, the distribution E0 changes sharply: The field near the anode, E0, decreases; that near the cathode, E(d), increases, and the entire distribution in the interior becomes flatter. At an intensity I1, which causes a complete screening of the impurity charge by the charge of photogenerated holes, the field distribution in the interior is approximately flat, and (in the case N(t) less-than-or-equal-to 10(13) cm-3) we have E0 almost-equal-to E(d) almost-equal-to V/d. At an intensity close to I1, the field profile is linear, while the current is a linear function of the intensity. The values of I1 and the current j (I1) are independent of the impurity concentration. The results obtained in this study indicate that it is possible to control an electric field in a structure by means of low light fluxes.
